Commercial Soft Contact Lenses Engineered with Zwitterionic Silver Nanoparticles for Effectively Treating Microbial Keratitis

The introduction of various drugs onto commercial soft contact lenses (CLs) has emerged as an effective strategy for treating microbial keratitis (MK) because drug-loaded CLs can maintain a controlled drug concentration which leads to enhanced drug bioavailability and reduced side effects in ocular tissues. In this study, silver nanoparticles modified with zwitterionic poly (carboxybetaine-co-dopamine methacrylamide) copolymer (PCBDA@AgNPs) as novel anti-infective therapeutics were prepared and firmly immobilized onto soft CLs through mussel-inspired surface chemistry. The obtained PCBDA@AgNPs-CL remained the excellent transparency of commercial CLs and exhibited strong and broad-spectrum antimicrobial activities. We systematically explored the mechanism and found that the functional CLs can effectively inhibit the growth of microbial biofilms via a synergic “resist–kill–remove” strategy due to the zwitterionic surface and sustained release of silver ions. Significantly, in vitro cell cytotoxicity and in vivo subcutaneous implantation experiments proved the outstanding biosafety of PCBDA@AgNPs-CL. Furthermore, PCBDA@AgNPs-CL was successfully employed for the in vivo treatment of MK rabbit models, demonstrating excellent abilities to eradicate microbe-induced ocular infections and to prevent the destruction and irreversible structural alterations of corneal tissues. Collectively, PCBDA@AgNPs-CL is therefore a highly promising therapeutic device to significantly boost the efficacy for MK treatment.